were standing just back from the main gate of the castle in a military formation. They were standing there occasionally swinging their swords and then freezing in the middle of a swing. It was quite cool to watch.
There were people in black clothing running around checking makeup after every little take of filming. The guys that were in the military formation were wearing black clothing with chain mail down their legs and had metal plates on their chests and were wearing metal helmets and each had a large sword.
There was one guy at the front of them all that wasn't wearing a helmet and had long blackish hair. The filming going on at that stage showed a couple of soldiers running out of the castle and attacking the lead guys and getting killed. Then the people that had been just standing in a big formation suddenly charged at the castle and about 8 rockets that were white in colour fired down from atop the castle wall and some of the men fell dead.
To the right is one of the concept pictures. The armour and helmets that you can see are a lot like the ones that I saw at Helm's Deep.